Rotor Cooling Passage Layout for Wound-Field Electrical Machines
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Solution Overview
Problem
Conventional techniques for cooling field windings in wound-field rotating electrical machines are ineffective in promoting heat dissipation across the entire winding, particularly at the axial end portions, leading to insufficient cooling of the middle sections.
Innovation Solution
A wound-field rotating electrical machine design incorporating a rotor core with tooth portions, non-magnetic members, and cooling medium flow passages that extend axially with inclined or stepped configurations to facilitate cooling medium distribution, ensuring effective cooling from the axial end to the middle portions of the field winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cooling medium flow passage is purely axial, then structure is simple, but cooling coverage is insufficient
Solution Approach 1:
The cooling medium flow passage incorporates radial components through inclined portions while maintaining axial portions, creating a three-dimensional flow path. This dimensional enhancement improves cooling coverage and effectiveness without significantly complicating the overall structure, as the inclined portions are integrated within the existing rotor core slots.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively cools the entire field winding, enhancing heat dissipation and reducing drag losses by ensuring uniform oil distribution and contact with the rotor winding.
Implementation Method 1
the cooling medium flow passage has a radially outermost radial position that is located further toward a radially outer side, at the second position than at the first position
Implementation Method 2
the cooling medium flow passage has an inclined portion or a step portion between a first position in the axial direction and a second position, in the axial direction, that is closer to a center, in the axial direction, of the rotor core than the first position
Data Source
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AI summary
There is disclosed a wound-field rotating electrical machine, including: a stator; and a rotor rotatably disposed coaxially with the stator with a gap in a radial direction between the rotor and the stator. The rotor includes: a rotor core including a plurality of tooth portions provided in a circumferential direction; a field winding wound on the plurality of tooth portions; and non-magnetic members extending in an axial direction, in a plurality of slots formed between the plurality of tooth portions. Each of the non-magnetic members includes a cooling medium flow passage extending in the axial direction. The cooling medium flow passage has an inclined portion or a step portion between a first position in the axial direction and a second position, in the axial direction, that is closer to a center, in the axial direction, of the rotor core than the first position. The cooling medium flow passage has a radially outermost radial position that is located further toward a radially outer side, at the second position than at the first position, by the inclined portion or the step portion.